Manufacture of polytrimethylene ether glycol

Abstract

A process of manufacture of polytrimethylene ether glycol comprising:(a) polycondensing reactant comprising diol selected from the group consisting of 1,3-propanediol, 1,3-propanediol dimer and 1,3-propanediol trimer or mixtures thereof in the presence of acid polycondensation catalyst to form polytrimethylene ether glycol;(b) adding water to the polytrimethylene ether glycol to form an aqueous mixture;(c) heating the aqueous mixture to hydrolyze acid esters formed during the acid catalyzed polycondensation;(d) adding to the hydrolyzed aqueous mixture organic solvent that is miscible with polytrimethylene ether glycol to form (i) organic phase containing the polytrimethylene ether glycol and residual acid polycondensation catalyst from the polycondensing and (ii) aqueous phase;(e) separating the aqueous phase and the organic phase;(f) adding base to the separated organic phase to neutralize the residual acid polycondensation catalyst by forming salts of the residual acid polycondensation catalyst;(g) separating the organic phase into (i) liquid phase comprising the polytrimethylene ether glycol, the organic solvent and any residual water, and (ii) solid phase comprising the salts of the residual acid polycondensation catalyst and the base which is unreacted; and(h) removing the organic solvent and the residual water from the liquid phase to obtain polytrimethylene ether glycol.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to an improved process for purifying polytrimethylene ether glycol.BACKGROUND OF THE INVENTION

[0002] Polytrimethylene ether glycol and its uses have been described in the art. Preferred methods for preparation of polytrimethylene ether glycol involve acid catalyzed polycondensation of 1,3-propanediol. For example, U.S. Pat. No. 6,720,459, which is incorporated herein by reference, discloses a continuous process for preparation of polytrimethylene ether glycol from 1,3-propanediol using a polycondensation catalyst, preferably an acid catalyst.

[0003] WO99 / 01496, which is incorporated herein by reference, discloses a process for the purification of polyethers includes the steps of (a) heating a polyether glycol with water for a time and at temperature sufficient to substantially hydryrolyze esters formed during polymerization, (b) separating the polyether from the water, and (c) subjecting the polyether recovered from step (b) to ...

Examples

examples

[0067]The 1,3-propanediol utilized in the examples was prepared by biological methods described in U.S. patent application Ser. No. 10 / 839,188, filed May 5, 2004, which is incorporated herein by reference and had a purity of >99.8%

example 1

[0074]This example describes purification of polytrimethylene ether glycol utilizing toluene as added water-immiscible solvent

[0075]1,3-Propanediol (11.9 kg) and 108 g of sulfuric acid were charged into a 22 L glass flask and then heated at 166+ / −1° C. under nitrogen for 24 hours to produce polytrimethylene ether glycol. During the reaction, by-product water was removed by nitrogen sparging.

[0076]After the polymerization step, 4 kg of de-ionized water was added and the resulting mixture was held at 95° C. for 4 hours under nitrogen to hydrolyze the acid ester formed during the acid catalyzed polycondensation.

[0077]After hydrolysis, 2.6 kg of toluene was added, followed by stirring for 10 minutes at 95° C. Then the agitation was stopped. About 20–30 minutes were required for the mixture to separate into two phases, the organic phase at the top and the aqueous phase at the bottom.

[0078]Based on titration of a sample of the top layer, 4.0 g of calcium hydroxide was added to the organic...

example 2

[0086]This example describes preparation of polytrimethylene ether glycol utilizing toluene as added water-immiscible solvent

[0087]Polymerization of 1,3-propanediol was carried out as described above for Comparative Example 2. After the polymerization step, 4 kg of de-ionized water was added and keep the resulting mixture was held at 95° C. for 4 hours under nitrogen to hydrolyze the acid ester formed during the acid catalyzed polycondensation.

[0088]After hydrolysis, 2.6 kg of toluene was added followed by stirring for 10 minutes at 95° C. Then the agitation was stopped. About 20–30 minutes were required for the mixture to separate into two phases, the organic phase at the top and the aqueous on the bottom.

[0089]Based on titration of a sample of the top layer, 5.0 g of calcium hydroxide was added to the organic phase to neutralize the residual acid catalyst, followed by stirring at 70° C. for 1 hour.

[0090]After neutralization, the mixture was filtered at 15 psig nitrogen to remove s...

FIELD OF THE INVENTION

[0001] The present invention relates to an improved process for purifying polytrimethylene ether glycol.BACKGROUND OF THE INVENTION

[0002] Polytrimethylene ether glycol and its uses have been described in the art. Preferred methods for preparation of polytrimethylene ether glycol involve acid catalyzed polycondensation of 1,3-propanediol. For example, U.S. Pat. No. 6,720,459, which is incorporated herein by reference, discloses a continuous process for preparation of polytrimethylene ether glycol from 1,3-propanediol using a polycondensation catalyst, preferably an acid catalyst.

[0003] WO99 / 01496, which is incorporated herein by reference, discloses a process for the purification of polyethers includes the steps of (a) heating a polyether glycol with water for a time and at temperature sufficient to substantially hydryrolyze esters formed during polymerization, (b) separating the polyether from the water, and (c) subjecting the polyether recovered from step (b) to ...

Examples

examples

[0067]The 1,3-propanediol utilized in the examples was prepared by biological methods described in U.S. patent application Ser. No. 10 / 839,188, filed May 5, 2004, which is incorporated herein by reference and had a purity of >99.8%

example 1

[0074]This example describes purification of polytrimethylene ether glycol utilizing toluene as added water-immiscible solvent

[0075]1,3-Propanediol (11.9 kg) and 108 g of sulfuric acid were charged into a 22 L glass flask and then heated at 166+ / −1° C. under nitrogen for 24 hours to produce polytrimethylene ether glycol. During the reaction, by-product water was removed by nitrogen sparging.

[0076]After the polymerization step, 4 kg of de-ionized water was added and the resulting mixture was held at 95° C. for 4 hours under nitrogen to hydrolyze the acid ester formed during the acid catalyzed polycondensation.

[0077]After hydrolysis, 2.6 kg of toluene was added, followed by stirring for 10 minutes at 95° C. Then the agitation was stopped. About 20–30 minutes were required for the mixture to separate into two phases, the organic phase at the top and the aqueous phase at the bottom.

[0078]Based on titration of a sample of the top layer, 4.0 g of calcium hydroxide was added to the organic...

example 2

[0086]This example describes preparation of polytrimethylene ether glycol utilizing toluene as added water-immiscible solvent

[0087]Polymerization of 1,3-propanediol was carried out as described above for Comparative Example 2. After the polymerization step, 4 kg of de-ionized water was added and keep the resulting mixture was held at 95° C. for 4 hours under nitrogen to hydrolyze the acid ester formed during the acid catalyzed polycondensation.

[0088]After hydrolysis, 2.6 kg of toluene was added followed by stirring for 10 minutes at 95° C. Then the agitation was stopped. About 20–30 minutes were required for the mixture to separate into two phases, the organic phase at the top and the aqueous on the bottom.

[0089]Based on titration of a sample of the top layer, 5.0 g of calcium hydroxide was added to the organic phase to neutralize the residual acid catalyst, followed by stirring at 70° C. for 1 hour.

[0090]After neutralization, the mixture was filtered at 15 psig nitrogen to remove s...